Undervolting with power saving features (P31)

[ermi]

I have a GA-P31-DS3L with an E5200.

I want to undervolt it, while keeping the power saving features enabled. So that when the CPU is in idle its frequency and voltage get reduced. (like it was done here, for example)

I did undervolt the CPU in the BIOS, but CPU-Z (and Speedfan) shows always the same voltage (1.2 V) in idle and load, even when the frequency gets reduced. I tried turning C1E and EIST off (one at a time) and it was the same.

What's the reliable method to do make it work?
Is CPU-Z even a good indicator of what's going on with CPU voltage?
Should I keep EIST or C1E enabled? Which of these two?

I'm hoping someone has a similar motherboard and went through this.

[BillyBuerger]

From what I've seen, this is dependent on the motherboard. I've used mostly Gigabyte boards as of late and they have an offset voltage you can apply to the CPU. So it will drop the voltage by 0.1V from the normal voltage at both idle and load. But if your board only has a single CPU voltage setting, by setting that you're overriding EIST and telling it to always run at that one voltage. It might be that it's automatically turning off EIST when you do this. The idea that you would be using this to overclock in which case you might not care about EIST. If you have no other options in your BIOS, then you're probably out of luck for any hardware undervolt.

The one option you might have is something like RMClock. It can allow you to tweak multiplier and voltage settings inside of windows. You would have to set your BIOS to default to keep EIST working most likely. It's an older program that doesn't work well on newer CPUs like the Core i CPUs. But it worked great on my old Pentium M systems and laptops. It should work fine with a E5200 CPU.

[ermi]

Thanks. I tried RMClock but it didn't seem to have any actual effect over the voltages (even tho its monitoring part showed it did - the stability tests and CPU-Z said otherwise). Maybe I needed to tweak some more stuff..

Anyway for now I reduced the voltage in BIOS from 1.25 to 1.175 (1.15 wasn't stable). Max freq is the default 2.5 GHz.